九年级中考复习：whether和if区别【含答案】

whether 和if区别

whether和if都可以引导宾语从句，表示“是否”，在口语或间接引语中两者可以互换使用。如：

I wonder if / whether I can get some advice from you.

Ask him whether / if he can come.

但在有些情况下，whether和if的用法有一定区别。

1. whether引导的从句常可以与连词or或or not直接连用，而if一般不能。如：

正： Let me know whether you can come or not.

误： Let me know if you can come or not.

2. 当宾语从句提到句首时，只能用whether引导，而不能用if。如：

正：Whether it is true or not, I can’t tell.

误：If it is true or not, I can’t tell.

3. whether可以引导带to的不定式，if则不能。如：

正：I don’t know whether to accept or refuse.

误：I don’t know if to accept or refuse.

4. whether及其引导的成分可放于介词之后，作介词的宾语，但if不能。如：

正： I worry about whether I hurt her feelings.

误： I worry about if I hurt her feelings.

5. whether可以引导从句，作主语、表语或同位语，而if不能。如：

正： It was uncertain whether he would come.

误： It was uncertain if he would come.

正： His first question was whether Tom had arrived yet.

误： His first question was if Tom had arrived yet.

正： We must consider the question whether we will take these measures.

误： We must consider the question if we will take these measures.

强化练习：

1. The question has not been answered ____ Taiwan will be included on the Olympic

torch relay route.

A．that B．whether C．which D．if

2. You have not yet answered my question _____ I can join in the party tonight or not.

A. whether

B. if

C. that

D. which

3．— I d like to invite you to a party this evening.

—Thank you, but _____ I’ll be free I m not sure at the moment.

A. while

B. if

C. when

D. whether 4．---What are you anxious about?

---___________

A. If we succeed

B.That we can succeed

C. Do we succeed

D.Whether we can succeed

5. Only when _____ the painting _____ decide ______the painting is worth buying.

A.he sees, he can ,whether

B. does he see, can he, if

C. he sees, can he ,whether

D. sees he, he can,that

6. _____ English is his favourite subject

A. I asked him if

B. I asked him that whether

C. I asked him that

D. I asked him which

7. _____ they’ll go to the Summer Palace ____ the weather.

A. If; depends on

B. Whether; depends upon

C. Whether; depended on

D. If; depended upon

8.It isn’t quite _____ ______ he will be prese nt at the meeting.

A. sure; whether

B. sure; if

C. certain; whether

D. certain; that

9. _____ the 2008 Olympic will be held in Beijing is not known yet.

A. Whether

B. If

C. Whenever

D. That

巧记whether与if异同讲课稿

巧记w h e t h e r与i f 异同

巧记whether与if异同 主从表从同位从，if不用whether用； discuss和介词后，whether引宾从； 不定式、or not后在跟，whether独能显神通； 宾从若是否定句，if发挥其功用； 避免歧义要慎重，其他情况可换用。 一、引导主语从句，常用whether． (1)Whether the meeting will be held is uncertain．会议是否召开还不能确定． (2)It is unknown whether he will come．他是否来还不知道。 3.Whether we’ll go camping depends on the weather. 二、引导表语从句常用whether (1).The question is whether he can finish the work by the end of this week． 问题是到这周末他是否能完成这个工作。 (2).What we want to know is whether he will come to speak to us． 我们想知道的是他能否来给我们讲话。 3.The question is whether it is worth doing. 三、引导同位语从句，常用whether. (1).The question whether he will come is important．他是否来这个问题很重要。 (2).The plan whether we’ll go outing tomorrow hasn’t been made．明天我们是否郊游这个计划还没订。 (3).The question whether we need it has not been decided. 四、引导宾语从句。引导及物动词的宾语从句，用whether, if皆可； 介词的宾语从句，一般只用whether引导；

九年级中考复习：whether和if区别【含答案】

whether 和if区别 whether和if都可以引导宾语从句，表示“是否”，在口语或间接引语中两者可以互换使用。如： I wonder if / whether I can get some advice from you. Ask him whether / if he can come. 但在有些情况下，whether和if的用法有一定区别。 1. whether引导的从句常可以与连词or或or not直接连用，而if一般不能。如： 正： Let me know whether you can come or not. 误： Let me know if you can come or not. 2. 当宾语从句提到句首时，只能用whether引导，而不能用if。如： 正：Whether it is true or not, I can’t tell. 误：If it is true or not, I can’t tell. 3. whether可以引导带to的不定式，if则不能。如： 正：I don’t know whether to accept or refuse. 误：I don’t know if to accept or refuse. 4. whether及其引导的成分可放于介词之后，作介词的宾语，但if不能。如： 正： I worry about whether I hurt her feelings. 误： I worry about if I hurt her feelings. 5. whether可以引导从句，作主语、表语或同位语，而if不能。如： 正： It was uncertain whether he would come. 误： It was uncertain if he would come. 正： His first question was whether Tom had arrived yet. 误： His first question was if Tom had arrived yet. 正： We must consider the question whether we will take these measures. 误： We must consider the question if we will take these measures. 强化练习： 1. The question has not been answered ____ Taiwan will be included on the Olympic

whether和if的用法区别

whether和if的用法区别 whether与if作“是否”讲，在用法上有相同之处，也有不同之处。 一、相同之处。 和if都能引导宾语从句，常置于see,ask,learn,tell,wonder,doubt,find out等动词之后。 如：He asked me whether/is I could help him. I want to know whether/if he lives there. 和if都可用it作形式主语从句中。如：it's uncertain whether/if he'll come this evening. 3.在be uncertain/doubtful之后，常用whether引导宾语从句，有时也可以用if，如：We are uncertain whether/if Mary will come. 二、不同之处。 可置于句首引导主语从句，而if不能。如：___the 2000 Olympic Games will be in Beijing is not known yet. 答案是C。 可用在介词之后，引导宾语从句，而If则不能。如：Success depends on whether we make evough effort. 可引导表语从句，if则不能。如：The puestion is whether it is not worth doing. 4.在名词之后引导同位语从句时，用whether而不用if。如：The question whether the students answered correctly should be decided by the teacher. 后可接不定式，而if不能。如：Please tell us whether to go or stay here. 6.在有些动词（如discuss）之后，只能用whether，而不用if引导宾语从句。如：We discussed whether we should close the shop. 7.在引导否定概念in宾语从句时，只能用if，而不用whether.如：he asked me if I hadn't finished my work. 英语时态一般现在时表示现在、经常或习惯的动作或状态和普遍现象、常识或客观真理；一般过去时用于过去某一时间内发生的或过去习惯性的动作或状态；一般将来时表示将要发生的动作或存在的状态，将来打算做的事情；现在完成时表示过去发生的动作造成目前的结果和对现在造成的影响或表示从过去延续至今的动作、状态和习惯等；将来完成时表示将来某时之前业已完成或发生的事情；过去完成时表示过去某时间之前已经发生的动作或状况，即过去的过去。注意每一种时态与其他时态的交叉使用情况。英语共有十六种时态，其表现形式如下(以study为例)： 一般时进行时完成时完成进行时 study studies am studying is studying are studying have studied has studied have been studying has been studying studied was studying were studying had studied had been studying shall study will study shall be studying will be studying shall have studied shall have been studying will have been studying should study would study should be studying would be studying should have studied would have studied should have been studying would have been studying 但考试中出现的一般有以下几种。 第一节一般现在时 一、表示一般性或经常发生的动作或状态 二、表示习惯性动作和状态或普遍的现象或常识 三、表示客观事实、客观规律和客观真理。在宾语从句中，即使主句的谓语动词用了过去时，只要从句表示的是客观真理，从句的谓语动词也要用一般现在时 四、祈使句必须用动词原形，其否定结构用“don`t＋动词原形”，如：Go and fetch some water. ／Don`t do that. 五、在反义疑问句中，如果主句用肯定句，那么，反问句用否定形式；如果主句用否定形式，那么，反问句就用肯定形式。而且前后在时态上要一致。但祈使疑问句用won`t you进行反问。如：See a film tonight, won`t you？ 注：①祈使句后边可用附加疑问句，以加强语气。如果祈使句用肯定形式，附加疑问句用否定形式；如果祈使句用否定形式，附加句用肯定形式；如：Come here next Sunday, won`t you ／Don`t tell it to anyone, will you ②但如果祈使句的前一句有了表示强烈肯定的语言环境，即使祈使句用了肯定形式，其附加成分也可以用“will you”(表示肯定，如

If和+whether的用法讲课教案

If和whether if不能替换whether的5种情况 1.正式文体中，句中有or not 时 2.引起主语，表语，同位语从句时 3.作介词宾语时 4.放不定式前，与不定式组成词组时 5.作discuss等词的宾语时 以上是if和whether表示"是否"之意的区别，此外，if还有加入的意思，引起条件状语从句；而whether 另有不管无论之意，引起让步状语从句 whether与if作“是否”讲，在用法上有相同之处，也有不同之处。 一、相同之处。 1.whether和if都能引导宾语从句，常置于see,ask,learn,tell,wonder,doubt,find out等动词之后。 如：He asked me whether/is I could help him. I want to know whether/if he lives there. 2.whether和if都可用it作形式主语从句中。如：it's uncertain whether/if he'll come this evening. 3.在be uncertain/doubtful之后，常用whether引导宾语从句，有时也可以用if，如：We are uncertain whether/if Mary will come. 二、不同之处。 1.whether可置于句首引导主语从句，而if不能。如：___the 2000 Olympic Games will be in Beijing is not known yet. A.whether B.If C.Whether D.That 答案是C。 2.whether可用在介词之后，引导宾语从句，而If则不能。如：Success depends on whether we make evough effort. 3.whether可引导表语从句，if则不能。如：The puestion is whether it is not worthdoing. 4.在名词之后引导同位语从句时，用whether而不用if。如：The puestion whether the students answered correctly should be decided by the teacher. 5.whether后可接不定式，而if不能。如：Please tell us whether to go or stay here. 6.在有些动词（如discuss）之后，只能用whether，而不用if引导宾语从句。如：We discussed whether we should close the shop. 7.在引导否定概念in宾语从句时，只能用if，而不用whether.如：he asked me if I hadn't finished my work. whether和if都可以引导宾语从句，表示“是否”，在口语或间接引语中两者可以互换使用。如： I wonder if / whether I can get some advice from you. Ask him whether / if he can come. 但在有些情况下，whether和if的用法有一定区别。 1. whether引导的从句常可以与连词or或or not直接连用，而if一般不能。如： 正：Let me know whether you can come or not. 误：Let me know if you can come or not. 2. 当宾语从句提到句首时，只能用whether引导，而不能用if。如： 正：Whether it is true or not, I can’t tell. 误：If it is true or not, I can’t tell. 3. whether可以引导带to的不定式，if则不能。如： 正：I don’t know whether to accept or refuse.

if、 whether 用法总结

whether,if if和whether通用，都表示“是否”的意思。一般来说，后者比较正式，在口语中前者常用来代替后者。但两者有时具有不同的暗示。用whether时，正反两面的选择意义较强，问话人并不在意回答是肯定还是否定；而用if时，则比较强调单方面，即正面，问话人希望得到肯定的回答。另外，还要注意以下几点： 一、whether和if都可以与or not连用；但写在一起时，只能用whether，不能用if。如： I don't care whether (或if) it will rain or not． I don't care whether or not it will rain. (不用if) 二、在引导宾语从句时，应注意： 1、表示“是否”时，两词都能引导宾语从句。 I wonder if/whether you can examine him now． 2、宾语从句移置句首时，用whether，不用if。

Whether it is true or not，I can't say． 3、宾语从句为否定形式时，通常用if，而不用whether。 I asked Tom if Mary wouldn’t come． 4、作discuss等词的宾语，用whether不用if。 We discussed whether we should buy the gift for him． 三、在下列情况下，只能用whether，不能用if。 1、与不定式连用时，只能用whether． He can't decide whether to accept or refuse． 2、在介词后，只能用whether。 Everything depends on whether he is ready． 3、在名词后作同位语时，只能用whether。

If 和whether的区别 (含 讲解+习题+答案)教学文稿

If 和whether的区别 if和whether都可译为\"是否\",二者引导宾语从句时通常可以互相替换,口语中多用if 代替whether.例如：Ask if/whether he plans to come to the meeting. 而以下几种情况中, 只能用whether: 1. 强调两方面的选择,特别是句中有or not时.如： Let me know whether you can come or not. 2. 宾语从句前置时.如： Whether this is true, I can\'t say. 3. 引导主语、表语、同位语从句时.如： Whether the football game will be played depends on the weather. （主语从句） The question is whether he can do it. （表语从句） The question whether we should go with them must be decided at once. （同位语从句） 4. 在介词之后作介词的宾语时.如： I haven\'t settled the question of whether I\'ll go back home. 5. 在不定式前与不定式一起组成词组时.如： Whether to go or stay is still a question. 6. 在discuss, decide 等动词后作宾语时.如： We discussed whether we should go there by plane. 值得注意的是：if还可以引导条件状语从句,是\"假如；如果\"之意,而whether可以引导让步状语从句,是\"不管；无论\" 之意.如： If you ask him, he will help you. I shall go, whether you come with me or stay at home. 一、if或whether引导宾语从句时,作“是否”讲,常放在动词ask 、see 、say 、know 和find out等后面.一般情况下,两者常可换用,在口语中多用if.如： 例1 Nobody knows whether (if) it will rain tomorrow. 没有人知道明天是否下雨. 例2 Lucy asked whether (if) they had a cotton sweater .露西问他们是否有棉制的羊毛衣. 二、if或whether引导宾语从句时,要注意三个方面,即连词、语序和时态. 1 if或whether不能和that 或其它连词（副词）同时使用,也不能省去.如： 例3 我不知道他今天是否会来. [误] I don’t know that if(whether) he will come here today . [正] I don’t know if(whether) he will come here today . 例4他走过来看看猫是否出了毛病. 误] He came to see what if (whether) there was wrong with his cat . [正] He came to see if (whether) there was wrong with his cat . 2 if或whether引导的宾语从句时,虽具有疑问意义,但从句语序应用陈述句语序.如：例5 Did you know the way to the hospital ? The old woman asked me . The old woman asked me .if (whether) I knew the way to the hospital .老妇人问我是否知道去医院的路. 3 if或whether引导的宾语从句应和主句的时态保持一致.即主句为一般现在时,从句用

If和whether的区别含讲解+习题+答案.docx

I f和w h e t h e r的区别 if 和 whether都可译为\"是否\",二者引导宾语从句时通常可以互相替换代替 whether.例如：Ask if/whether he plans to come to the meeting. 几种情况中 , 只能用 whether:,口语中多用 if 而以下 1.强调两方面的选择 ,特别是句中有 or not 时.如： 2.宾语从句前置时 .如： 3.引导主语、表语、同位语从句时 .如： Whether the football game will be played depends on the weather.（主语从句） The question is whether he can do it.（表语从句） The question whether we should go with them must be decided at once.（同位语从句） 4.在介词之后作介词的宾语时 .如： 5.在不定式前与不定式一起组成词组时 . 如： Whether to go or stay is still a question. 6. 在 discuss, decide等动词后作宾语时 .如： We discussed whether we should go there by plane. 值得注意的是：if 还可以引导条件状语从句 ,是\" 假如；如果 \" 之意 ,而 whether 可以 引导让步状语从句 ,是 \" 不管；无论 \" 之意 .如： If you ask him, he will help you. I shall go, whether you come with me or stay at home. 一、if 或 whether引导宾语从句时 ,作“是否”讲 , 常放在动词 ask 、see 、say 、know 和 find out 等后面 . 一般情况下 ,两者常可换用 , 在口语中多用 if. 如： 例 1 Nobody knows whether (if) it will rain tomorrow.没有人知道明天是否下雨. 例 2 Lucy asked whether (if) they had a cotton sweater .露西问他们是否有棉制的羊毛衣 . 二、 if 或 whether引导宾语从句时 ,要注意三个方面 ,即连词、语序和时态 . 1 if或 whether不能和 that 或其它连词（副词）同时使用,也不能省去 . 如： 例 3我不知道他今天是否会来 . [ 误 ] I don ’ t know that if(whether) he will come here today . [ 正 ] I don ’ t know if(whether) he will come here today . 例 4他走过来看看猫是否出了毛病 . 误] He came to see what if (whether) there was wrong with his cat . [ 正 ] He came to see if (whether) there was wrong with his cat . 2 if 或 whether引导的宾语从句时,虽具有疑问意义,但从句语序应用陈述句语序. 如：例5 Did you know the way to the hospital ? The old woman asked me . The old woman asked me .if (whether) I knew the way to the hospital .老妇人问我是否知道去医院的路. 3 if 或 whether引导的宾语从句应和主句的时态保持一致. 即主句为一般现在时,从句用

if和whether的用法

if和whether的用法： 一、if或whether引导宾语从句时，作“是否”讲，常放在动词ask 、see 、say 、know和find out等后面。直接引语如果为一般疑问句，变为间接引语时就用if或whether引导，并把疑问句语序变为陈述句语序。一般情况下，两者常可换用，在口语中多用if。如： 二、if或whether引导宾语从句时，要注意三个方面，即连词、语序和时态。 ◆if或whether不能和that 或其它连词（副词）同时使用，也不能省去。 ◆if或whether引导的宾语从句时，虽具有疑问意义，但从句语序应用陈述句语序。 ◆if或whether引导的宾语从句应和主句的时态保持一致。即主句为一般现在时，从句用任一种时态；主句为一般过去时，从句则用过去时中的任一种时态。 ◆如果主句中的时态为一般过去时，从句中的时态要求发生相应的变化与主句的时态保持一致。（表示客观规律，自然现象和真理的则不变。） 三、if和whether的区别： ◆在动词不定式之前只能用whether 。 ◆在whether ……or not 的固定搭配中。 ◆在介词后，只能用whether。 ◆宾语从句放在句首表示强调时，只能用whether 。

◆用if会引起歧义时，只用whether。如用whether可避免歧义 eg：“Are they from France?”He asked me . →He asked me if they were from France. My physics told us that light travels faster than sound. 物理老师告诉我们光比声音传播的快。

if 和 whether 用法区别

if 和 whether 用法区别 1. 引导宾语从句 在引导宾语从句时，whether和if通可以互换，在 ask,care,doubt,know,learn,see,tell,try,wonder等动词之后尤其如此。例They don’t care a bit whether my reports are good or bad.. I am not sure if/whether I’ll have time. 但是，必须注意以下几点： 1）如果从句是否定结构，则用if不用whether.例如： I don’t care if he doesn’t show up .他来不来我都不在乎。 但是，当doubt是否定式时，则不用whether或if，要改用that,因为句子本身已没有“怀疑”或选择之意。度比较： She never doubt for a moment that she was right.她对自己是正确的这一点从不怀疑。 I doubt if that was what he wanted. 2)宾语从句前置时只能用whether,如： Whether he lives there,I want to know. 3）在decide,dicuss等动词后，通常只跟whether引导的宾语从句。如： They dicussed whether they should close the shop. 4)出现在介词后面的宾语从句只能用whether引导，如： It all depends on whether she likes the boss or not .一切都取决于她是否喜欢这位上司。 5）句中含有引导条件状语从句的if时，用whether不用if，如： Bill asked whether ,if I got the job,I’d move to York.比尔问如果我得到这份工作是否还要迁到约克。 2．引导主语从句 主语从句位于句首时，用whether不用if Whether they win or lose is all the same to me. Whether it will do us harm or good remains to be seen. 但是，当采用形式主语it,而将主语从句后置时，用whether和if均可（尽管whether更常用）： It makes no difference to me whether/if it’s foggy or clear..(高二册，第220页) 3．引导表语从句 引导表语从句时，一般用whether.例如： The question is whether they can cooperate with us.问题是他们能否与我们合作。 4．引导同位语从句时一般用whether.例如： We will soon discuss the problem whether we should take some effective measures to protect the animals and plants in our region.我们很快将讨论是否应该采取一些有效措施来保护本地区的动植物这一问题。 5．引导让步状语从句 1)引导让步状语，一般用whether.例如： Whether you like it or not ,you’ll have to do it . Whether the weather is good or bad ,they will set off as they planned.无论天气是好是坏，他们都将按计划启程。

If和whether的区别(含讲解+习题+答案)(可编辑修改word版)

If 和whether 的区别 if 和whether 都可译为\"是否\",二者引导宾语从句时通常可以互相替换,口语中多用if 代替whether.例如：Ask if/whether he plans to come to the meeting. 而以下几种情况中, 只能用whether: 1.强调两方面的选择,特别是句中有or not 时.如： Let me know whether you can come or not. 2.宾语从句前置时.如： Whether this is true, I can\'t say. 3.引导主语、表语、同位语从句时.如： Whether the football game will be played depends on the weather. （主语 从句） The question is whether he can do it. （表语从句） The question whether we should go with them must be decided at once. （同位语从句） 4.在介词之后作介词的宾语时.如： I haven\'t settled the question of whether I\'ll go back home. 5.在不定式前与不定式一起组成词组时.如： Whether to go or stay is still a question. 6.在discuss, decide 等动词后作宾语时.如： We discussed whether we should go there by plane. 值得注意的是：if 还可以引导条件状语从句,是\"假如；如果\"之意,而whether 可以引导让步状语从句,是\"不管；无论\" 之意.如： If you ask him, he will help you. I shall go, whether you come with me or stay at home. 一、if 或whether 引导宾语从句时,作“是否”讲,常放在动词ask 、see 、say 、know 和find out 等后面.一般情况下,两者常可换用,在口语中多用if.如： 例1 Nobody knows whether (if) it will rain tomorrow. 没有人知道明天是否下雨. 例2 Lucy asked whether (if) they had a cotton sweater .露西问他们是否有棉制的羊毛衣. 二、if 或whether 引导宾语从句时,要注意三个方面,即连词、语序和时态. 1if 或whether 不能和that 或其它连词（副词）同时使用,也不能省去.如： 例3 我不知道他今天是否会来. [误] I don’t know that if(whether) he will come here today . [正] I don’t know if(whether) he will come here today . 例4 他走过来看看猫是否出了毛病. 误] He came to see what if (whether) there was wrong with his cat . [正] He came to see if (whether) there was wrong with his cat . 2if 或whether 引导的宾语从句时,虽具有疑问意义,但从句语序应用陈述句语序.如： 例5 Did you know the way to the hospital ? The old woman asked me . The old woman asked me .if (whether) I knew the way to the hospital . 老妇人问我是否知道去医院的路.

if与whether的区别

1、引导宾语从句 在引导宾语从句时，whether 和if 通可以互换，在ask,care,doub,know,learn,msee,tell,try,wonder等动词之后尤其如此。例如： I don’t know if/whether I can help you. They don’t care a bit whether my reports are good or bad.. I wonder if you can examine him now.(高一册第十四页) I am not sure if/whether I’ll have time. 但是，必须注意以下几点： 1）如果从句是否定结构，则用if不用whether.例如： Well,think,and see if the most religious people aren’t those who fell that this life doesn’t gice them all they want.好，你想，那最虔诚的宗教徒，是不是就是那此觉得这现实的人生没有完全满足自己欲望的人？ Dinner was almost over when Dan,still looking hungry,grinned and asked Dave if he wasn’t going to have some bread.晚饭快吃完的时候丹（他看上去还没吃饱）笑着问戴维还要不要吃些面包。 I don’t care if he doesn’t show up .他来不来我都不在乎。 Let me know if you can’t meet me at Jackson and Throop Streets Wednesday afternoon at two o’clock.星期三下午奉告警方，你是否能在杰逊街和思鲁街的黑心角来跟我相会。（＜嘉莉妹妹＞＝ 当然，对某些句子，人们可能会有不同的理解。如上面最后两列中的if 也可理解为引导条件状语从句： 他不来我也不在乎。 如果你在星期三下午二时不能和我在杰克逊街和思鲁街的黑心角相会，请通知我。 但是，当doubt是还定式时，则不用whether或if，要改用that,因为句子本身已没有“怀疑”或选择之意。度比较： I don’t doubt that you are honest.我不怀疑你的诚实。 She never doubt for a moment that she was right.她对自己是正确的这一点从不怀疑。 I doubt whether it’s true. I doubt if that was what he wanted. 2)宾语从句前置时只能用whether,如： Whether he lives there,I want to know.

whether和if都可以引导宾语从句

whether和if都可以引导宾语从句，表示“是否”，在口语或间接引语中两者可以互换使用。如： I wonder if / whether I can get some advice from you. Ask him whether / if he can come. 但在有些情况下，whether和if的用法有一定区别。 1. whether引导的从句常可以与连词or或or not直接连用，而if一般不能。如： 正：Let me know whether you can come or not. 误：Let me know if you can come or not. 2. 当宾语从句提到句首时，只能用whether引导，而不能用if。如： 正：Whether it is true or not, I can’t tell. 误：If it is true or not, I can’t tell. 3. whether可以引导带to的不定式，if则不能。如： 正：I don’t know whether to accept or refuse. 误：I don’t know if to accept or refuse. 4. whether及其引导的成分可放于介词之后，作介词的宾语，但if不能。如： 正：I worry about whether I hurt her feelings. 误：I worry about if I hurt her feelings. 5. whether可以引导从句，作主语、表语或同位语，而if不能。如： 正：It was uncertain whether he would come. 误：It was uncertain if he would come. 正：His first question was whether Tom had arrived yet. 误：His first question was if Tom had arrived yet. 正：We must consider the question whether we will take these measures. 误：We must consider the question if we will take these measures.

巧记whether与if异同

巧记whether与if异同 主从表从同位从，if不用whether用； discuss和介词后，whether引宾从； 不定式、or not后在跟，whether独能显神通； 宾从若是否定句，if发挥其功用； 避免歧义要慎重，其他情况可换用。 一、引导主语从句，常用whether． (1)Whether the meeting will be held is uncertain．会议是否召开还不能确定． (2)It is unknown whether he will come．他是否来还不知道。 3.Whether we’ll go camping depends on the weather. 二、引导表语从句常用whether (1).The question is whether he can finish the work by the end of this week． 问题是到这周末他是否能完成这个工作。 (2).What we want to know is whether he will come to speak to us． 我们想知道的是他能否来给我们讲话。 3.The question is whether it is worth doing. 三、引导同位语从句，常用whether. (1).The question whether he will come is important．他是否来这个问题很重要。 (2).The plan whether we’ll go outing tomorrow hasn’t been made．明天我们是否郊游这个计划还没订。 (3).The question whether we need it has not been decided. 四、引导宾语从句。引导及物动词的宾语从句，用whether, if皆可； 介词的宾语从句，一般只用whether引导； 在whether…or not结构中，口语用if也可以，但whether or not，不可换用if；宾语从句放句首只能用whether引导。whether 和if常与or not 连用，但whether 和or not既可以合起来使用，也可以分开使用。if和or not只能分开使用。宾语从句放句首只能用whether引导。 (1).He asked whether/if they would come or not. (2).I want to know whether/if he lives there．我想知道他是否住在那儿。 (3).I worry about whether I hurt her feeling．我担心是否伤了她的感情。 (4).I asked him whether/if he would come or not，或 I asked whether or not he would come．我问他来还是不来。 (5)．Whether it is true，I can’t say．这件事是否真实，我不能说。 五、与不定式构成起名词作用的短语，用作主语，表语，宾语时，只用whether，不用if. 例如：I don’t know whether to see her．我不知道是不是去看她。 六、当if引导从句，有可能与条件状语相混而产生此义时，要用whether．例如： Let me know if you can come．释义有：第一，把know看作不及物动词，由if引导条件状语从句，意为“如果你能来，请通知我”；第二，把know当作及物动词，由if引导宾语从句，意为“告诉我你是否能来”。所以，要表达后者意义，必须把if换为whether。 I’ll tell you whether he is busy. (如果将句中的whether改成if,则又歧义，因为if 还有“如果”之意) 学以致用：

whether if 区别加习题

由whether,if 引导的宾语从句 （一）由whether,if 引导的宾语从句 由whether(if)引导的宾语从句，实际上是一般疑问句演变而来的。意思是“是否”。宾语从句要用陈述句语序。一般说来，在宾语从句中whether与if可以互换使用，但在特殊情况下if与whether是不能互换的。 例句：I wonder whether(if) they will come to our party. （二）只能用whether，不能用if引导的宾语从句 1.在带to的不定式前：We decided whether to walk there. 2.在介词的后面：I’m thinking of whether we should go to see the film. 3.直接与or not连用时 例句：I can’t say whether or not thet can come on time. 4.当强调宾语从句并将其提前时只能用whether。 如:Whether I'll have time to go with you I am not sure.我很难说我 们是否有时间跟你们一起去。 5.当whether和or 连用表示明确的选择时。 如:He asked me whether I wanted to go there by train or by bus.他问 我是想乘火车还是坐公共汽车去那里。 6.动词discuss，decide,consider，sure等后习惯上也常用Whether引导从句， 不用if。 They discussed whether they should leave at once.他们讨论 了是否应该马上离开。 We discussed whether the house should be sold. 我们讨论了这 房子是否应卖掉。 （三）其他只能用whether不能用if的情况 1.表语从句用whether引导不用if. 如:①The doubt was whether you had broken the beautiful vase. 疑问是你是否打坏了这只漂亮的花瓶。 2 同位语从句用whether引导不用if. 如: The question whether we'll build another lecture building hasn't been settled. 是否要另建一幢教学楼的问题还未决定。 3位于句首的主语从句只能用.whether。 如： Whether they win or lose is all the same to me. 他们是赢是输於我都一样.（此时whether不能换作if ） It's doubtful whether there'll be any seats left. 说不上还有没有空座位了. (此句whether能换作if)